1. Field of Invention
The invention relates to a headlamp for a vehicle which incorporates a composite reflector. Further, the invention relates to a composite reflector that includes an extension member connected to the front of the composite reflector.
2. Discussion of Related Art
A conventional headlamp for a vehicle often employs an extension member which is disposed in the front of a reflector so as to surround a front opening of the reflector. The extension member has a shape so as not to interfere with the reflector when the reflector is being inclined to adjust the aim of the headlamp.
A four-lamp type headlamp incorporates a pair of reflectors, each reflector having a light source bulb joined thereto. Generally these pair of reflectors are disposed in parallel with each other in the lateral direction and set to be offset in a longitudinal direction. Moreover, in general, these two reflectors are integrally formed into a composite reflector housing. Examples of such headlamps are disclosed in U.S. Pat. Nos. 4,807,094 and 5,003,446 to Mateos et al. and Nagengast et al., respectively.
When attempting to provide the extension member for the headlamp for a vehicle which incorporates the above-mentioned type of composite reflector housing, various problems might occur depending on the positioning of the pair of reflectors that comprise the composite reflector housing. For example, the composite reflector housing has a connecting portion formed between the pair of reflectors. Therefore, the extension member has to be formed into a shape for preventing interference with the connecting portion.
In case where the front openings of the respective reflectors are disposed close together or overlapped with each other in a front view of the headlamp, if the extension member is provided and configured to avoid interference with the aforementioned connecting portion, the position of the opening periphery of the extension member that faces the front opening of the rear reflector has to be shifted from the original position to a position closer to the optical axis of the rear reflector. Therefore, the effective reflecting area of the rear reflector is reduced, resulting in deteriorated light distribution and reduced performance of the headlamp. Thus, the required design of the headlamp cannot be obtained as originally intended.